Phenylalkenylcarboxylic acids and their esters

ABSTRACT

Phenylalkenylcarboxylic acid and esters thereof of the general formula I ##STR1## where X is hydrogen or fluorine, R 1  is hydrogen, C 1  C 6  -alkyl, C 5  - or C 6  -cycloalkyl, (C 1  -C 4  -alkoxy)-C 2  -C 4  -alkyl or (C 1  -C 4  -alkylthio)-C 2  -C 4  -alkyl; W is a divalent radical --CH═CR 2  --; --CH═CY--; --CH═CR 2  --CH 2  --; --CH═CR 2  --CH═CR 3  -- or ##STR2## where Y is chlorine or bromine and R 2  and R 3  are each hydrogen or C 1  -C 4  -alkyl, with the proviso that X is not F when W is --CH═CR 2  --, their manufacture, and their use as herbicides.

The present invention relates to phenylalkenylcarboxylic acids which aresubstituted in the 5-position by tetrahydro-2H-isoindole-1,3-dione(tetrahydrophthalimide) and their esters, a process for theirpreparation and their use as herbicides.

It is known that certain isoindoledione-substituted cinnamates can beused as herbicides. These compounds, which are disclosed in JapanesePreliminary Published Application 59/115 358, are of the general formulaZ ##STR3## where Y is hydrogen or methyl and Q is alkyl, in particularethyl. Furthermore, European Laid-Open Application 68,822 discloses thestructure Z¹ : ##STR4##

However, their herbicidal action and their toleration by crops are in noway satisfactory in practice.

It is an object of the present invention to provide herbicides which arebetter tolerated and at the same time more effective against weeds.

We have found that this object is achieved by the novel compounds of thegeneral formula I ##STR5## where X is hydrogen or fluorine, R¹ ishydrogen, C₁ -C₆ -alkyl, C₅ - or C₆ -cycloalkyl, (C₁ -C₄ -alkoxy)-C₂ -C₄-alkyl or (C₁ -C₄ -alkylthio)-C₂ -C₄ -alkyl, W is a divalent radical--CH═CR² --, --CH═CY--, --CH═CR² --CH₂ --, --CH═CR² --CH═CR³ -- or##STR6## where Y is chlorine or bromine and R² and R³ are each hydrogenor C₁ -C₄ -alkyl, with the proviso that X is not F when W is --CH═CR²--.

The novel substances (I) are very suitable, for example, for controllingweeds in wheat, corn, rice and soybean.

The substances of the formula I are obtained, for example, by reactingan aniline of the formula II with the anhydride III in a suitablesolvent at from 40° to 120° C. in the course of, in general, not morethan 24 hours (scheme A): ##STR7##

The reaction is advantageously carried out in a suitable solvent, suchas an aliphatic hydrocarbon (eg. hexane or naphtha), an aromatichydrocarbon (eg. toluene or xylene), an ether (eg. tetrahydrofuran ordiethylene glcyol dimethyl ether), a lower fatty acid (eg. acetic acidor propionic acid) or a mixture of the latter with water. The reactionproduct is isolated in a conventional manner by extraction,precipitation and, if necessary, subsequent recrystallization and, ifrequired, is purified by chromatography.

The anhydride III is a known intermediate. Anilines of the formula IIare obtained by subjecting an appropriate nitro compound to catalytichydrogenation or to reduction with a suitable reducing agent (eg. ironin methanol/glacial acetic acid) to give II (scheme B): ##STR8##

The nitro compounds IV, which are likewise novel, can be obtained in aknown manner, and it is possible to use various methods depending on thenature of the radical W:

1. If W is --CH═CR² --, the nitro compound (2) is obtained, for exampleby nitration of the known α-alkylcinnamate (1) according to scheme (1):##STR9##

Where X is H, the nitration is advantageously carried out with 96-100%strength nitric acid at from -10° to 0° C. The corresponding fluorinecompound can also be nitrated in concentrated sulfuric acid as adiluent.

The parent ester (1) is obtained in a conventional manner by esterifyingthe acid (5), which is prepared from benzaldehyde (3) by reaction withmalonic acid or a carboxylic anhydride (4) (Scheme 2): ##STR10##

The conditions which are suitable for the preparation of (5) and (5a)are known; the Perkin condensation is described by, for example,Johnson, Org. Reactions 1 (1942), 210 et seq.; a synoptic report of theKnoevenagel condensation appears in Org. Reactions 15 (1967), 204.

A special case is encountered when, in (2), both X and R¹ are hydrogen:##STR11##

The 2-chloro-5-nitrocinnamic acid (2a) is obtained directly from thenitrobenzaldehyde (6) and the anhydride (4) (scheme 3): ##STR12##

The analogous reaction of (6) with malonic acid gives the cinnamic acid(2b) which is unsubstituted in the α-position: ##STR13##

The corresponding cinnamates 2c and 2d are obtained by esterification of2a and 2b.

2. If W is the (halogenated) radical --CH═CY--, the required nitrocompound (8) is prepared either by halogenation of the ester (1a) (=1where R² is H) and subsequent dehydrogenation followed by nitration(scheme 4), or by halogenation and dehydrohalogenation of anitrocinnamate (2d), as shown in scheme 5: ##STR14##

The preferred method for the preparation of a compound Ib where W is--CH═CY--CO₂ R¹ is, however, via halogenation and dehydrogenation of thestructure Ia (scheme 6): ##STR15##

While bromine readily undergoes an addition reaction with Ia (Y═Br), anaddition reaction with chlorine requires the measures described in theExamples.

The bases required for dehydrohalogenation are, for example,triethylamine, pyridine or α-picoline.

The solvent preferably used in the addition reaction with halogen is1,1,1-trichloroethane or glacial acetic acid, while thedehydrohalogenation is carried out in methylene chloride, ethyl acetate,1,1,1-trichloroethane or the like.

3. If W contains a chain of more than two carbon atoms, the process forthe preparation of the required nitro compound depends on whether X isfluorine or hydrogen:

3.1 If X is hydrogen, a nitrocinnamaldehyde (9) or the nitrobenzaldehyde(6) is used as the starting material. The required carbon chain W isthen obtained by reacting (9) either with malonic acid in pyridine orwith the oxazoline (10) in toluene or subjecting (9) to a Perkincondensation with the anhydride (4). ##STR16## Alternatively, the carbonchain W can be obtained by reacting (6) with the phosphonate (11) or (9)with the phosphonate (12) in the presence of sodium hydride in dioxaneor dimethylformamide (Horner-Emmons reaction). ##STR17## (12) isprepared according to Angew. Chem. 80 (1968, 364.

3.2 If, on the other hand, X is fluorine, the carbon chain is firstsynthesized by Knoevenagel condensation or a Horner-Emmons reaction fromthe benzaldehyde (13) or the cinnamaldehyde (14) ##STR18## and the nitrogroup is then introduced.

The Examples described provide more details on the synthesis of a chainof more than 2 carbon atoms.

4. Finally, if W is ##STR19## the required aniline derivative IIIa canbe obtained by reacting an appropriate nitrocinnamylidene malonate withNaBH₄ in the presence of copper(II) acetate.

A typical example of the preparation of a compound I is the following:

EXAMPLE 1 Desired compound ##STR20##

1.1 Methyl2-chloro-4-fluoro-5-N-(3,4,5,6-tetrahydrophthalimido)-cinnamate wasfirst prepared similarly to the process described in JapanesePreliminary Published Application 59/115 358.

1.2 5 g of bromine, dissolved in 20 ml of CH₂ Cl₂, are added dropwise toa solution of 10 g of methyl cinnamate in 100 ml of CH₂ Cl₂, and themixture is then heated at the boil for a further hour. It is allowed tocool to 25° C., 8 ml of triethylamine are added and stirring is carriedout for 14 hours at 25° C. The mixture is extracted twice with 50 ml ofwater, dried and evaporated down. The residue is dissolved in tolueneand the solution is chromatographed over silica gel. After the toluenehas been stripped off, a solid (mp. 121°-123° C. yield 9.5 g, ie. 78%;active ingredient No. 1--1 in Table 1) remains. The other compounds inthis Table were obtained by appropriate modification from other startingmaterials.

EXAMPLE 2 Desired compound: active ingredient 2--2 in Table 2

2.1 4-(2-Chloro-5-nitrophenyl)-3-methyl-3-butenoic acid

A solution of 6.6 g of tetraethyl dimethylaminomethylenediphosphonate in25 ml of dioxane is added dropwise to a suspension of 0.6 g of sodiumhydride in 25 ml of absolute dioxane with slight cooling (23°-26° C.)and the mixture is stirred for one hour. Thereafter, a solution of 4.5 gof 3-(2-chloro-5-nitrophenyl)-2-methyl-2-propenal in 25 ml of dioxane isadded dropwise and the mixture is then heated at 50° C. for 12 hours.The solvent is then removed in a rotary evaporator, the residue isdissolved in diethyl ether (150 ml) and the solution is extracted twiceby shaking with water. Drying and evaporation give 6.8 g (84%) of anoily liquid of the structure: ##STR21## By boiling this enamine for onehour with 200 ml of concentrated HCl, pouring the mixture into 1 l ofice water and extracting with diethyl ether, drying and evaporatingdown, 4.4 g of liquid are obtained.

2.2 Methyl 4-(2-chloro-5-nitrophenyl)-3-methyl-3-butenoate

4.3 g of the acid obtained according to 2.1 are dissolved in 60 ml ofmethanol at room temperature and the solution is saturated with HCl gas,the temperature increasing to about 29° C. After the solution has stoodfor 16 hours, the methanol is distilled off, the residue is dissolved indiethyl ether and the solution is washed with aqueous Na bicarbonate andthen with water, dried with MgSO₄ and evaporated down, 3.3 g (72%) ofthe desired ester being obtained.

2.3 Methyl 4-(2-chloro-5-aminophenyl)-3-methyl-3-butenoate

A solution of 3.3 g of the nitroarylbutenoate obtained under 2.2 in amixture of 17 ml of methanol and 17 ml of glacial acetic acid is addeddropwise to a suspension of 4.1 g of iron powder in a mixture, heated to60° C., of 34 ml of methanol and 9 ml of glacial acetic acid. Themixture is heated at the boil for 2 hours and then filtered, thefiltrate is evaporated virtually to dryness and the residue is stirredwith 150 ml of ethyl acetate. The solution is washed with water, driedand evaporated down to give 3.2 g of an oil.

2.42-{4-Chloro-3-[(2'-methyl-3'-methoxycarbonyl-1'-propenyl)-phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione

3.0 g of the aniline derivative obtained according to 2.2 and 1.9 g oftetrahydrophthalic anhydride are dissolved in 20 ml of glacial aceticacid and the solution is heated at the boil for 2 hours. Thereafter, thesolvent is evaporated off, the residue is dissolved in ethyl acetate andthe solution is washed with aqueous Na bicarbonate and then with water,dried and evaporated down. The oily residue is chromatographed oversilica gel with 95:5 hexane/acetone. Finally, 1.4 g of the productremain as an oil;

n_(D) ²⁴ =1.5579.

(Active ingredient 2--2 in Table 2; other compounds can be prepared in asimilar manner)

EXAMPLE 3 Desired compound2-{4-Chloro-3-[(4'-methoxycarbonyl-1',3'-butadienyl)phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(active ingredient 4-1 in Table 4)

3.1 5-(2'-Chloro-5'-nitrophenyl)-2,4-pentadienoic acid

10.15 g of 2-chloro-5-nitrocinnamaldehyde are addedd to a solution of6.05 g of malonic acid in 20 ml of pyridine at 25° C., followed by 0.45g of piperidine. The mixture is then heated at the boil for 3 hours.After cooling, it is poured into a solution of 20 ml of concentrated HClin 50 ml of ice water, the product being precipitated. The crude product(11.9 g) is filtered off under suction, washed with water and driedunder reduced pressure at 50° C. and then chromatographed in 8:2toluene/acetone over silica gel, 5.6 g of the desired acid beingobtained as a white solid.

3.2 Methyl 5-(2'-chloro-5'-nitrophenyl)-2,4-pentadienoate

A solution of 5.4 g of the carboxylic acid obtained according to 3.1 in60 ml of methanol is saturated with HCl gas and left to stand for 16hours. The solvent is evaporated off, after which the residue is stirredwith NaHCO₃ /water, filtered off under suction and washed with water.Drying under reduced pressure at 50° C. gives 3.5 g of the ester (mp.132° C.; 62% of theory).

3.3 Methyl 5-(2'-chloro-5'-aminophenyl)-2,4-pentadienoate

9 ml of glacial acetic acid are poured into a suspension of 4.3 g ofiron powder in 35 ml of methanol, which is heated at 60° C., andsubsequently a solution of 3.4 g of the ester described under 3.2 in amixture of 17 ml of methanol and 17 ml of glacial acetic acid is addeddropwise. The mixture is refluxed for 1 hour and then evaporated down,the residue is stirred with ethyl acetate and the solution is washedwith water, dried and evaporated down to give 2.9 g (96% of theory) of acolorless oil.

3.4 Reaction with 3,4,5,6-tetrahydrophthalic anhydride

2.2 g of tetrahydrophthalic anhydride and 2.9 g of the anilinederivative obtained according to 3.3 are dissolved in 25 ml of glacialacetic acid and the solution is stirred for two hours at 40° C. and thenfor 2 hours at 110° C. After the solvent has evaporated off, the oilyresidue is dissolved in hexane and the solution is chromatographed oversilica gel. 2.3 g (59% of theory) of a compound of melting point127°-130° C. are obtained. According to NMR analysis, the product is amixture of the following stereoisomers: ##STR22##

EXAMPLE 4 Desired compound2-{4-Chloro-3-[(4'-methoxycarbonyl-2'-methyl-1',3'-butadienyl)-phenyl]}-4,5,6,7-tetahydro-2H-isoindole-1,3-dione(active ingredient 4-2 in Table 4)

4.1 5-(2'-Chloro-5'-nitrophenyl)-4-methyl-2,4-pentadienoic acid

0.3 g of a 40 percent strength NaHSO₃ solution is added to a mixture of9 g of 2-chloro-5-nitro-α-methylcinnamaldehyde and 10.4 g of2,4,4-trimethyloxazoline in 50 ml of toluene, and the mixture isrefluxed for 10 hours. It is evaporated down, and 10 ml of water and 10ml of concentrated HCl are added to the crude product of the structure##STR23## Heating at 100° C. for 7 hours results in cleavage of theoxazoline ring. The crude product is filtered off under the suction,washed with water and dried. Yield: 7.1 g (66%), mp. 178°-185° C.

4.2 Methyl 5-(2'-chloro-5'-nitrophenyl)-4-methyl-2,4-penadienoate

The acid obtained according to 4.1 is esterified with methanol/HCl; 49%yield (mp.: 87°-90° C.).

4.3 Methyl 5-(2'-chloro-5'-aminophenyl)-4-methyl-2,4-pentadienoate

The reduction of the nitro compound prepared according to 4.2 is carriedout as described under 3.3. 2.9 g (97%; mp.: 47°-50° C.) of the anilinederivative of the following structure: ##STR24## The aniline derivativeis prepared according to 4.3 is reacted with tetrahydrophthalicanhydride in glacial acetic acid in the manner described. The crudeproduct is purified by chromatography over silica gel with 1:1hexane/acetone and is recrystallized from 80% strength methanol to give1.5 g (35% of theory) of the active ingredient (mp.: 160°-162° C.) whichis listed in Table 4 as compound No. 4-2. The compound is presumably amixture of stereoisomers.

EXAMPLE 5 Desired compound2-{4-Chloro-3-[(4'-ethoxycarbonyl-3'-methyl-1',3'-butadienyl)-phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(active ingredient 4-3 in Table 4)

5.1 Ethyl 5-(2'-chloro-5'-nitrophenyl)-2-methyl-2,4-pentadienoate(Horner-Emmons reaction)

A solution of 5.3 g of diethyl3-methyl-3-ethoxycarbonyl-2-propane-1-phosphonate in 10 ml ofdimethylformamide (DMF) is added dropwise at 0°-10° C. to a suspensionof 0.65 g of 80 percent strength NaH in 30 ml of absolute DMF.

After the mixture has been stirred for two hours at 40° C., evolution ofhydrogen is complete; a solution of 3.7 g of2-chloro-5-nitrobenzaldehyde in 10 ml of DMF is then added dropwise, andstirring is continued for 5 hours at 60° C. Thereafter, 5 ml of methanolare added dropwise, 20 ml of concentrated HCl are introduced and themixture is extracted with 3 times 100 ml of diethyl ether and washedonce with water. Evaporation and chromatography over silica gel withtoluene gives 3.8 g (67% of theory) of a solid of melting point 80°-82°C. and of the following structure: ##STR25##

5.2 Reduction of the nitro group

The nitro compound obtained according to 5.1 was reduced with iron inethanol/glacial acetic acid. A yellowish oil is obtained in 96% yieldand is converted to the active ingredient without further purification.

5.3 1.35 g of tetrahydrophthalic anhydride and 2.35 g of the anilinederivative obtained according to 5.2 in 25 ml of glacial acetic acid arereacted in the manner described. Working up gives 2.1 g (59% of theory)of the active ingredient of melting point 123°-125° C., which is listedin Table 4 as compound 4-3.

EXAMPLE 6 Desired compound2-{4-Chloro-3-[(4'-methoxycarbonyl-2',4'-dimethyl-1',3'-butadienylphenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(active ingredient 4--4 in Table 4)

6.1 5-(2'-Chloro-5'-nitrophenyl)-2,4-dimethyl-2,4-pentadienoic acid(Perkin condensation)

22.6 g of 2-chloro-5-nitro-α-methylcinnamaldehyde and 9.6 g of sodiumpropionate are added to 16.3 g of propionic anhydride and the mixture isstirred for 22 hours at 140° C. After cooling, the reaction mixture ispoured into 100 ml of water, brought to pH 10 (NaOH) and extracted withethyl acetate. After the aqueous phase has been acidified withconcentrated HCl, the precipitate which has separated out is filteredoff with suction, washed with water and dried. 18 g (64% of theory) of ayellow solid of melting point 180°-182° C. and of the followingstructure are obtained: ##STR26##

6.2 Methyl 5-(2'-chloro-5'-nitrophenyl)-2,4-dimethyl-2,4-pentadienoate

The acid is esterified with methanol/HCl. The ester of melting point88°-90° C. is obtained in 78% yield.

6.3 Methyl 5-(2'-chloro-5'-aminophenyl)-2,4-dimethyl-2,4-pentadienoate

The nitro compound is reduced with iron in methanol/glacial acetic acid.12.3 g (95%) of a yellowish oil is obtained and is used without furtherpurification.

6.42-{4-Chloro-3-[(4'-methoxycarbonyl-2',4'-dimethyl-1',3'-butadienyl)-phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione

12.3 g of the aniline derivative obtained according to 6.3 and 7 g of2,3-tetramethylenemaleic anhydride in 70 ml of glacial acetic acid arestirred for 2 hours at 40° C. and then heated to the boil for two hours.After the solvent has been separated off in a rotary evaporator, theresidue is chromatographed over silica gel with 9:1 n-hexane/acetone andthen recrystallized once from methanol. 12.5 g (68% of theory) of acolorless solid of melting point 105°-107° C. are obtained (compound4--4 in Table 4).

The other compounds listed in Table 4 can be obtained in a similarmanner.

EXAMPLE 7 Desired compound2-{4-Chloro-3-[(4',4'-bis-methoxycarbonyl-1'-butenyl)-phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(active ingredient 5-1 in Table 5)

7.1 Dimethyl 2-chloro-5-nitrocinnamylidenemalonate

2 ml of piperidine is added to a mixture of 21.7 g ofchloro-5-nitrocinnamaldehyde and 26.4 g of dimethyl malonate in 20 ml ofDMF and the mixture is heated at 60° C. for 12 hours. Thereafter, alllow boilers are stripped off under 0.1 bar and at a bath temperature of50° C. in a rotary evaporator, the residue is poured into water, and theprecipitated solid is stirred with methanol. Filtration under suctionand drying under reduced pressure at 50° C. give 15.6 g (48% of theory)of a yellow solid of melting point 167°-168° C.

7.2 Dimethyl 2-chloro-5-aminocinnamylmalonate 50 ml of a freshlyprepared saturated solution of Cu(II) acetate in methanol are added to asolution of 4.8 g of the nitro compound obtained according to 7.1 in 100ml of dioxane. Thereafter, 2 g of NaBH₄ are added a little at a time andthe mixture is stirred for 4 hours at 35° C. 300 ml of diethyl ether arethen added and the mixture is extracted with NaHCO₃ solution. Theaqueous phase is discarded and the ether phase is dried and evaporateddown to give 4.18 g (95%) of an oil which is of the following structure:##STR27##

7.3 Tetrahydroisoindole-1,3-dione derivative

2.1 g of 2,3-tetramethylenemaleic anhydride and 4.1 g of the oilobtained according to 7.2 in 25 ml of acetic acid are stirred for 1 hourat 40° C. and then heated for a further hour at 110° C. The solvent isstripped off and the residue is then chromatographed over silica gelwith n-hexane to give 3.5 g (58%) of an oil (n²⁴ =1.5538) of thefollowing structure: ##STR28##

EXAMPLE 8 Desired compound2-{4-Chloro-3-[(4',4'-bis-methoxycarbonyl-2'-methyl-1'-butenyl)-phenyl]}-4,5,6,7-tetrahydro-2H-isoindole-1,3-dione(active ingredient 5-2 in Table 5)

8.1 2-Chloro-5-nitro-α-methylcinnmaldehyde

A solution of 2.4 g of NaOH in 20 ml of water is poured into asuspension of 111 g of 2-chloro-5-nitrobenzaldehyde in 500 ml ofmethanol and the mixture is cooled to 10° C. 42 g of propionaldehyde arethen added dropwise. A clear solution is formed, from which aprecipitate begins to separate out in the course of 1 hour. Stirring iscarried out for 16 hours at 20°-25° C., after which the pH is brought to5 with acetic acid, the solid is filtered off under suction and thefiltrate is evaporated down. The residue and the solid are combined anddissolved in methylene chloride, and the solution is washed with water,dried and evaporated down. The crude product is stirred thoroughly with1:1 petroleum ether/ether, filtered off under suction and dried.

Yield: 109 g (81%); mp. 102°-104° C.

8.2 Dimethyl 2-chloro-5-nitro-α-methylcinnamylidenemalonate

22.6 g of the aldehyde obtained according to 8.1 are added to a solutionof 26.4 g of dimethyl malonate in 20 ml of tetrahydrofuran (THF) andfinally a solution of 2 ml of piperidine in 10 ml of THF is addeddropwise. The mixture is then heated at 60° C. for 4 hours. After themixture has cooled, the solvent is stripped off under reduced pressureand the residue is stirred with methanol, filtered off under suction anddried under reduced pressure. A yellow solid of melting point 100°-102°C. is obtained. The yield is 19.3 g (57%).

8.3 Dimethyl 2-chloro-5-amino-α-methylcinnamylmalonate

The nitro ester obtained in 8.2 is reduced with NaBH₄ in the presence ofcopper acetate in methanol in the manner described in Example 7.2. 1.4 g(63%) of the desired product are obtained in the form of an oil from 2.4g of 8.2 by this procedure. The structure is as follows: ##STR29##

8.4 Tetrahydroisoindole-1,3-dione derivative

The aniline derivative obtained in 8.3 is reacted with2,3-tetramethylenemaleic anhydride in glacial acetic acid using theprocedure in Example 7.3. 1.26 g (63%) of the active ingredient ofmelting point 84°-86° C., whose structure is shown in Table 5 forcompound 5-2, are obtained from 1.4 g of aniline derivative by thisprocedure. The other compounds in Table 5 can also be obtained in asimilar manner.

                  TABLE 1                                                         ______________________________________                                         ##STR30##                                                                    No.   X      Y      R.sup.1     Physical constant                             ______________________________________                                        1-1   F      Br     CH.sub.3    mp. 121-123° C.                        1-2   F      Br     C.sub.2 H.sub.5                                                                           mp. 105-110° C.                        1-3   F      Cl     CH.sub.3                                                  1-4   F      Cl     C.sub.2 H.sub.5                                           1-5   F      Br     n-C.sub.3 H.sub.7                                         1-6   F      Br     n-C.sub.4 H.sub.9                                                                         mp. 55-60° C.                          1-7   F      Br     n-C.sub.5 H.sub.11                                        1-8   F      Br     n-C.sub.6 H.sub.13                                                                        oil                                           1-9   F      Br     cyclo-C.sub.5 H.sub.9                                      1-10 F      Br     cyclo-C.sub.6 H.sub.11                                     1-11 F      Cl     (CH.sub.2).sub.2OCH.sub.3                                  1-12 F      Cl     (CH.sub.2).sub.2SCH.sub.3                                 ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                         ##STR31##                                                                    No.   X     R.sup.2 R.sup.1      Physical constant                            ______________________________________                                        2-1   H     H       CH.sub.3                                                  2-2   H     CH.sub.3                                                                              CH.sub.3     n.sub.D.sup.24 = 1.5579                      2-3   H     CH.sub.3                                                                              C.sub.2 H.sub.5                                           2-4   H     CH.sub.3                                                                              n-C.sub.4 H.sub.9                                         2-5   H     CH.sub.3                                                                              (CH.sub.2).sub.2 OCH.sub.3                                2-6   H     CH.sub.3                                                                              (CH.sub.2).sub.2SCH.sub.3                                 2-7   F     H       CH.sub.3                                                  2-8   H     C.sub.2 H.sub.5                                                                       CH.sub.3                                                  2-9   F     C.sub.2 H.sub.5                                                                       CH.sub.3                                                   2-10 H     C.sub.2 H.sub.5                                                                       C.sub.2 H.sub.5                                            2-11 H     C.sub.2 H.sub.5                                                                       n-C.sub.4 H.sub.9                                         ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                         ##STR32##                                                                    No.    X       R.sup.2   R.sup.1                                                                              Physical constant                             ______________________________________                                        3-1    F       C.sub.2 H.sub.5                                                                         CH.sub.3                                             3-2    F       C.sub.2 H.sub.5                                                                         C.sub.2 H.sub.5                                      3-3    F       i-C.sub.3 H.sub.7                                                                       CH.sub.3                                             3-4    F       n-C.sub.3 H.sub.7                                                                       CH.sub.3                                             3-5    F       n-C.sub.4 H.sub.9                                                                       CH.sub.3                                             ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                         ##STR33##                                                                    No.   X     R.sup.2                                                                              R.sup.3                                                                            R.sup.1     Physical constant                         ______________________________________                                        4-1   H     H      H    CH.sub.3    mp. 127-130° C.                    4-2   H     CH.sub.3                                                                             H    CH.sub.3    mp. 160-162° C.                    4-3   H     H      CH.sub.3                                                                           C.sub.2 H.sub.5                                                                           mp. 123-125° C.                    4-4   H     CH.sub.3                                                                             CH.sub.3                                                                           CH.sub.3    mp. 105-107° C.                    4-5   F     H      H    C.sub.2 H.sub.5                                       4-6   F     H      H    n-C.sub.3 H.sub.7                                     4-7   F     H      H    n-C.sub.4 H.sub.9                                     4-8   H     C.sub.2 H.sub.5                                                                      H    CH.sub.3                                              4-9   H     CH.sub.3                                                                             H    C.sub.2 H.sub.5                                        4-10 H     CH.sub.3                                                                             H    n-C.sub.4 H.sub.9                                      4-11 H     CH.sub.3                                                                             H    (CH.sub.2).sub.2OCH.sub.3                              4-12 H     CH.sub.3                                                                             H    (CH.sub.2).sub. 2SCH.sub.3                            ______________________________________                                    

                  TABLE 5                                                         ______________________________________                                         ##STR34##                                                                    No.   X      R.sup.2 R.sup.1     Physical constant                            ______________________________________                                        5-1   H      H       CH.sub.3    n.sub.D.sup.24 = 1.5538                      5-2   H      CH.sub.3                                                                              CH.sub.3    mp. 84-86° C.                         5-3   H      C.sub.2 H.sub.5                                                                       CH.sub.3                                                 5-4   H      H       C.sub.2 H.sub.5                                          5-5   H      H       n-C.sub.3 H.sub.7                                        5-6   H      H       n-C.sub.4 H.sub.9                                        5-7   H      CH.sub.3                                                                              C.sub.2 H.sub.5                                          5-8   H      CH.sub.3                                                                              n-C.sub.3 H.sub.7                                        5-9   H      CH.sub.3                                                                              n-C.sub.4 H.sub.9                                         5-10 H      CH.sub.3                                                                              (CH.sub.2).sub.2 OCH.sub.3                                5-11 H      CH.sub.3                                                                              (CH.sub.2).sub.2 OC.sub.2 H.sub.                          5-12 H      CH.sub.3                                                                              (CH.sub.2).sub.2 OC.sub. 4 H.sub.9                       ______________________________________                                    

The compounds according to the invention may be applied either pre- orpostemergence. If certain crop plants tolerate the active ingredientsless well, application techniques may be employed in which theherbicidal agents are sprayed from suitable equipment in such a way thatthe leaves of sensitive crop plants are if possible not touched, and theactive ingredients reach the soil, or the leaves of the unwanted plantsgrowing below them (post-directed, lay-by treatment).

The amount of active ingredient applied depends on the objective to beachieved, the time of the year, the plants to be combated with theirgrowth stage, and is from 0.005 to 3.0, and preferably from 0.015 to0.5, kg/ha.

The herbicidal action of the isoindoledione derivatives of the formula Ion the growth of test plants is demonstrated in greenhouse experiments.

The vessels employed were plastic flowerpots having a volume of 300 cm³,and which were filled with soil containing about 3.0% humus. The seedsof the test plants were sown separately, according to species.

For the postemergence treatment, the test plants were grown to a heightof from 3 to 15 cm, depending on growth shape, before they were treatedwith suspensions or emulsions of the active ingredients in water asvehicle, sprayed through finely distributing nozzles. Either plantswhich had been sown in the vessels and grown there were used, or theplants were first grown as seedlings. The application rates forpostemergence treatment were 0.015, 0.125 and 0.5 kg of activeingredient per hectare. No covers were placed on the vessels during thistreatment.

The pots were set up in the greenhouse-heat-loving species at from 20°to 36° C., and species from moderate climates at from 10° to 20° C. Theexperiments were run for from 2 to 4 weeks, during which time the plantswere tended with their reactions to the various treatments assessed. Thescale used for assessment was 0 to 100, 100 denoting non-emergence orcomplete destruction of at least the visible plant parts.

The plants used in the greenhouse experiments were:

    ______________________________________                                        Latin name       Common name                                                  ______________________________________                                        Amaranthus spp.  pigweed                                                      Arachis hypogaea peanuts (groundnuts)                                         Cassia tora      sicklepod                                                    Centaurea cyanus cornflower                                                   Chrysanthemum spp.                                                                             marigold                                                     Galium aparine   catchweed bedstraw                                           Ipomoea spp.     morningglory                                                 Lamium amplexicaule                                                                            henbit                                                       Mercurialis annua                                                                              annual mercury                                               Oryza sativa     rice                                                         Sesbania exaltata                                                                              hemp sesbania (coffeeweed)                                   Solanum nigrum   black nightshade                                             Triticum aestivum                                                                              wheat                                                        Veronica spp.    speedwell                                                    Viola spp.       violet                                                       Zea mays         Indian corn                                                  ______________________________________                                    

Compounds nos. 4-1, 4-2, 4--4 and 1--1 have, when applied postemergenceat a rate of 0.5 kg/ha, a strong herbicidal action on unwantedbroadleaved plants.

Compounds nos. 5-2, 5-1 and 2--2 have a herbicidal action when appliedpostemergence at a rate of 0.125 kg/ha.

Compound no. 4-2 has, when applied postemergence at a rate of 0.125kg/ha in wheat, a selective action on broadleaved weeds, while onlyinitial and slight temporary damage was caused to the wheat plants.

Compound no. 4-1 selectively combats unwanted plants when appliedpostemergence at a rate of 0.125 kg/ha to groundnuts, the latter onlysuffering brief damage which disappears later.

Unwanted broadleaved plants in wheat, rice and Indian corn are combatedwith 0.015 kg/ha of compound no. 1--1. If the crop plants suffer anydamage at all, it is only temporary and to the foliage.

In view of the wide variety of application methods available, thecompounds according to the invention, or agents containing them, may beused in a further large number of crops for combating unwanted plants.Examples are given below:

    ______________________________________                                        Botanical name          Common name                                           ______________________________________                                        Allium cepa             onions                                                Ananas comosus          pineapples                                            Arachis hypogaea        peanuts                                                                       (groundnuts)                                          Asparagus officinalis   asparagus                                             Avena sativa            oats                                                  Beta vulgaris spp. altissima                                                                          sugarbeets                                            Beta vulgaris spp. rapa fodder beets                                          Beta vulgaris spp. esculenta                                                                          table beets, red                                                              beets                                                 Brassica napus var. napus                                                                             rapeseed                                              Brassica napus var. napobrassica                                                                      swedes                                                Brassica napus var. rapa                                                                              turnips                                               Brassica rapa var. silvestris                                                 Camellia sinensis       tea plants                                            Carthamus tinctorius    safflower                                             Carya illinoinensis     pecan trees                                           Citrus limon            lemons                                                Citrus maxima           grapefruits                                           Citrus reticulata       mandarins                                             Citrus sinensis         orange trees                                          Coffea arabica (Coffea canephora,                                                                     coffee plants                                         Coffea liberica)                                                              Cucumis melo            melons                                                Cucumis sativus         cucumbers                                             Cynodon dactylon        Bermudagrass                                          Daucus carota           carrots                                               Elais guineensis        oil palms                                             Fragaria vesca          strawberries                                          Glycine max             soybeans                                              Gossypium hirsutum (Gossypium arboreum,                                                               cotton                                                Gossypium herbacem, Gossypium vitifolium)                                     Helianthus annuus       sunflowers                                            Helianthus tuberosus    Jerusalem                                                                     artichoke                                             Hevea brasiliensis      rubber plants                                         Hordeum vulgare         barley                                                 Humulus lupulus        hops                                                  Ipomoea batatas         sweet potatoes                                        Juglans regia           walnut trees                                          Lactuca sativa          lettuce                                               Lens culinaris          lentils                                               Linum usitatissimum     flax                                                  Lycopersicon lycopersicum                                                                             tomatoes                                              Malus spp.              apple trees                                           Manihot esculenta       cassava                                               Medicago sativa         alfalfa (lucerne)                                     Mentha piperita         peppermint                                            Musa spp.               banana plants                                         Nicotiana tabacum (N. rustical)                                                                       tobacco                                               Olea europaea           olive trees                                           Oryza sativa            rice                                                  Phaseolus lunatus       limabeans                                             Phaseolus mungo         mungbeans                                             Phaseolus vulgaris      snapbeans,                                                                    green beans,                                                                  dry beans                                             Pennisetum glaucum      pearl millet                                          Petroselinum crispum spp. tuberosum                                                                   parsley                                               Picea abies             Norway spruce                                         Abies alba              fir trees                                             Pinus spp.              pine trees                                            Pisum sativum           English peas                                          Prunus avium            cherry trees                                          Prunus domestica        plum trees                                            Prunus dulcis           almond trees                                          Prunus persica          peach trees                                           Pyrus communis          pear trees                                            Ribes sylvestre         redcurrants                                           Ribes uva-crispa        gooseberries                                          Ricinus communis        castor-oil plants                                     Saccharum officinarum   sugar cane                                            Secale cereale          rye                                                   Sesamum indicum         sesame                                                Solanum tuberosum       Irish potatoes                                        Sorghum bicolor (S. vulgare)                                                                          sorghum                                               Sorghum dochna          sorgo                                                 Spinacia oleracea       spinach                                                Theobroma cacao        cacao plants                                          Trifolium pratense      red clover                                            Triticum aestivum       wheat                                                 Vaccinium corymbosum    blueberries                                           Vaccinium vitis-idaea   cranberries                                           Vicia faba              tick beans                                            Vigna sinensis (V. unguiculata)                                                                       cow peas                                              Vitis vinifera          grapes                                                Zea mays                Indian                                                                        corn, sweet corn,                                                             maize                                                 ______________________________________                                    

To increase the spectrum of action and to achieve synergistic effects,the tetrahydroisoindolediones of the formula I may be mixed and appliedtogether with numerous representatives of other herbicidal orgrowth-regulating active ingredient groups. Examples of suitablecomponents are diazines, 4H-3,1-benzoxazine derivatives,benzothiadiazinones, 2,6-dinitroanilines, N-phenylcarbamates,thiolcarbamates, halocarboxylic acids, triazines, amides, ureas,diphenyl ethers, triazinones, uracils, benzofuran derivatives,quinolinecarboxylic acids, phenoxypropionic acid derivatives,cyclohexenones, etc.

It may also be useful to apply the tetrahydroisoindolediones of theformula I, either alone or in combination with other herbicides, inadmixture with other crop protection agents, e.g., agents for combatingpests or phytopathogenic fungi or bacteria. The compounds may also bemixed with solutions of mineral salts used to remedy nutritional ortrace element deficiencies. Non-phytotoxic oils and oil concentrates mayalso be added.

We claim:
 1. Phenylalkenylcarboxylic acid and esters thereof of theformula I ##STR35## where X is flourine; R¹ is a member selected fromthe group consisting of methyl and ethyl; and W is --CH═CBr--.
 2. Aherbicidal composition which comprises: an effective amount of acompound of the formula I as defined in claim 1 and a conventionalformulating agent.
 3. A process for combating the growth of unwantedplants, which comprises: applying to said plants or their habitat aneffective amount of a compound of the formula I as defined in claim 1.